Voltage Level Detector (CB22135E)

We found this circuit in an English documentation from the 80's. Transistors are general-purpose types.

Night Switch (CB12701E)
The circuit shown in the figure activates a small indicator lamp that will start to flash when the...
LM3900 Voltage Controlled Current Source (CB14211E)
The circuit shown is from National Semiconductor's Linear Applications Handbook. The LM3900 is a...
Oscillator for Bias and Erasing Recording Heads (CB1516E )
This circuit was found in a 1976 documentation. It can be used with old tape recording mechanisms for...